Vendor description: ------------------- "Extending the art & spirit of PHP, Zend Framework is based on simplicity, object-oriented best practices, corporate friendly licensing, and a rigorously tested agile codebase. Zend Framework is focused on building more secure, reliable, and modern Web 2.0 applications & web services, and consuming widely available APIs from leading vendors like Google, Amazon, Yahoo!, Flickr, as well as API providers and cataloguers like StrikeIron and ProgrammableWeb."

Vulnerability overview/description: ----------------------------------- The XmlRpc package of Zend Framework is vulnerable to XML eXternal Entity Injection attacks (both server and client). The SimpleXMLElement class (SimpleXML PHP extension) is used in an insecure way to parse XML data. External entities can be specified by adding a specific DOCTYPE element to XML-RPC requests. By exploiting this vulnerability an application may be coerced to open arbitrary files and/or TCP connections.

Other software that uses the XmlRpc package of Zend Framework is then also vulnerable to XML eXternal Entity Injection attacks!

Proof of concept: ----------------- For example, the loadXml function (Zend\XmlRpc\Request.php and Response.php) fails to disable external entities when parsing XML data. There is no call to the libxml_disable_entity_loader function before initializing the SimpleXMLElement class. Related code excerpt:

If a web application uses the Zend_XmlRpc_Server() class (Zend\XmlRpc\Server.php) to handle XML-RPC requests, it is possible to disclose arbitrary local files from the remote system. The following HTTP POST request to the vulnerable XmlRpc server application illustrates the exploitation of this vulnerability.

Vulnerable / tested versions: ----------------------------- The vulnerability has been verified to exist in versions 1.11.11 and 2.0.0beta4 of Zend Framework, which were the most recent versions at the time of discovery.

Furthermore, previous versions and 1.12.0 RC1 are also affected.

Older branches are also affected but won't be fixed by Zend as they are not maintained anymore. Their policy is to fix the current minor release and the immediate previous minor release.